The invention relates to a wheel, in particular for a motor vehicle, with a rim and a spider, where a bolted connection is provided in the area of the transition from the rim to the spider, in which a bolt head or a nut on the outside acts in combination with a contact surface on the spider.
Inside and outside here are understood to mean the sides of the wheel which they assume in the installed position on the vehicle.
Bolted connections of this type are frequently provided in the case of wheels for automobiles. For example, in the case of two-piece wheels, the rim and the spider are bolted together. In the case of three-piece wheels, the rim itself is in two parts, and both parts are attached to the spider with a single bolted connection.
In addition, even in the case of single-piece wheels, a bolted connection is frequently provided which does not fulfil any functional purpose, but which lends the wheel the stylish look of a more expensive, multi-piece wheel.
For example, a three-piece wheel is known from U.S. Pat. No. 4,770,220 in which the three parts of the wheel are connected by a bolt.
Furthermore, U.S. Pat. No. 5,343,920 describes a bolted connection for a multi-piece wheel, where a threaded bolt is first pressed into the wheel and the bolted connection is then made by means of a nut which is integrally joined to a flange and an extension piece.
Furthermore, a bolted connection for a three-piece wheel is known from DE-OS 23 61 066.
All these wheels have a spider formed as a plane surface, at least in the area of the bolted connection, where the outer edge of the spider, that is the area of the bolted connection, forms a surface perpendicular to the axis of the wheel.
Milling a cutout into the spider is also known, so that a bolt head or a nut in the tightened position is recessed with respect to the wheel surface. The disadvantage to this is that these parts of the wheel are particularly prone to becoming dirty because of the recessed contact surface, and the result is an unattractive visual effect from the wheel, which frequently serves as a focal design point on the vehicle, particularly, as in the case of bolted connections using a hexagon head or a 12-point head for the bolt or the nut, the cavities in the spider have to be selected considerably larger than the bolt head or the nut, in order to provide adequate access for the tool. In these cases, the area in particular between the bolt head (nut) and the base of the spider becomes dirty.
In as much as provision is made for a hexagon socket head, the cavity can be essentially selected exactly the same size as the bolt head, or the nut; the result is still an unattractive build-up of dirt in the area of the hexagon socket head, and besides that, hexagon socket head bolts have an awkward look, such as is often not desirable on expensive styled wheels.
This problem has since been partly solved by integrally casting in shoulders in the area of the bolted connection, which have a surface running perpendicular to the longitudinal axis of the wheel.
The integral forming of the shoulders at the time of the casting process for the spider represents considerable trouble and expense from the manufacturing standpoint. Beyond that, these shoulders give the wheel a crude appearance because of their size, since they have to be carried over into the spider using gradual transitions.
The object of the invention is, therefore, to provide a wheel with a bolted connection in the area between the rim and the spider, in which first of all dirt is prevented from collecting in the area of the bolted connection as far as possible, and in addition, the simplest possible production is ensured together with appealing visual qualities. At the same time, the wheel designer should have the greatest possible latitude at his disposal for the wheel design.
The object is achieved according to the invention in that the bolted connection comprises a spacer sleeve, which with one side acts in conjunction with the bolt head or the nut, and with the other side, with the contact surface (abuts against it) in such a way that the bolt head or the nut projects above the outer surface of the spider.
By using a spacer sleeve between the contact surface and the underside of the bolt head or the nut, the distance between the nut (bolt head) and the contact surface can be increased far enough so that the bolt head no longer lies directly on the contact surface. By having the bolt head or the nut project above the surface of the spider, tools can gain access to the bolt head (nut) with exceptional ease, in particular, since the bolt head is not in direct contact with the surface of the spider. Scratching the surface when loosening or tightening the bolt is thus avoided. In addition, the automobile is given a new unique styling look.
The invention is particularly advantageous in the case of curved or angled spiders or whose surfaces, at least in the area of the bolted connection, i.e., essentially in the area of the outer periphery of the spider, are curved or run at an angle. In the case of wheels on which the forward edge of the spider in cross section is curved in the area of the bolted connection, or runs at an angle to the perpendicular to the wheel rim axis, that is to say, it forms a cone, the problem always arises that a flat contact surface running perpendicular to the wheel axis has to be created for the bolted connection. By providing a spacer sleeve, the contact surface can be created in the spider surface by simple milling. At the same time, bolts which are easier to clean and have a visually more appealing outer contour can be used, where the contact surface can be formed in such a way that only a narrow gap remains between the spacer sleeve and the spider in the area of the spacer sleeve jacket, so that essentially no dirt collects in hard-to-clean areas.
Furthermore, as a result it is no longer necessary to cast integral shoulders on the spider in order to create a contact surface which simultaneously allows access to the bolt or nut with a tool.
In accordance with a first embodiment it can be provided that in cross section the outer edge of the spider is set back in the direction of the inside of the wheel in the area of the bolted connection, with respect to the area of the wheel axis of the spider. Inside of the wheel and outside of the wheel means here the side when it is in its operating position, i.e. facing towards the vehicle and facing away from the vehicle. As a result, a particularly pleasing wheel exterior is achieved. The spider then has an essentially conical form, where the lateral face of the cone can be straight or curved. However, a xe2x80x9cfunnel shapexe2x80x9d for the outer surface is also conceivable, i.e., a concave shape for the spider when viewed from the outer side.
In particular, it can also be provided that the spacer sleeve is an integral part of the bolted connection. That is to say, the bolted connection, or a part of the bolted connection, for example, the bolt or a nut, and the spacer sleeve can be joined to form a single part, where the result is a uniquely configured shape for the bolt head or the nut, which creates an especially attractive stylish appearance.
The spacer sleeve can have both a circular as well as a polygonal cross section, for example, rectangular or hexagonal where the cross section is perpendicular to the longitudinal axis.
Furthermore, it can be provided that the bolt head or the nut has a non-cylindrical outer contour, in particular a hexagonal or 12-point shape on its outer periphery or else an internal contour, in particular a hexagonal socket shape. Other shapes are possible for the nuts or the bolt heads.
The invention relates in addition to a wheel with a rim and a spider, in particular for a motor vehicle, where a bolted connection is provided in the area of the transition from the rim to the spider, in which a bolt head or a nut abuts on the outside against a contact surface on the spider, where the bolted connection comprises a spacer sleeve integrally attached to the bolt head or the nut, which with one of its sides acts in conjunction with the bolt head or the nut and with its other side with the contact surface in such a way that the bolt head or the nut projects above the outer surface of the spider and where the bolt head or the nut and the spacer sleeve do not have any external or internal flats and the bolted connection includes an anti-rotation element for tightening the bolted connection.
An embodiment of this kind for the nut or the bolt head, without any external or internal flats whatever, where the bolt head can be essentially formed as a cylinder, firstly gives special emphasis to the appearance, secondly the build-up of dirt can be further reduced. Finally, a design of this kind offers the advantage that with the wheel mounted to the vehicle no surfaces are provided from the outside to gain a purchase and loosen the bolted connection. Further theft protection is thereby achieved. Finally the design is particularly attractive because the spacer sleeve and bolt head or nut appear to be cast in one piece.
In order to ensure that the bolted connection is tightened, without having to apply counterpressure at the bolt head or the nut or the spacer sleeve which have no external or internal flats, the bolted connection has an anti-rotation element. This anti-rotation element must be designed so that it can withstand normal tightening torque. It is located on the side of the bolted connection which also includes the spacer sleeve.
It can be provided here that bolt head or nut and spacer sleeve are realized as cylindrical sections with different diameters, or that the part of the bolted connection visible on the outside can have different rotationally symmetrical form without flats, as for example, a smaller cylinder on top of a larger cylinder, however a conically tapering form can also be provided. The bolt head (nut) and/or the spacer sleeve can, for example, be tapered in addition, where the transition in the case of all shapes can be formed with or without a step. The transitions can be rounded.
The bolted connection can be formed in different ways. It can be provided that the bolted connection consists of a threaded rod and two nuts. However, it can also be provided that one of the nuts is connected in one piece to the threaded rod as a bolt head and forms a bolt. The threaded rod can be threaded over its entire length, but also only in sections.
A drilled passage, which can be furnished with or without a thread, can be provided for the bolted connection, where a bolted connection is made on the inside of the wheel by means of an additional nut, or else a bolt can be pushed through from the inside to the outside or inserted from the outside to the inside through the wheel rim.
Alternatively the bolted connection can also be formed solely by means of a threaded rod with an integrally attached bolt head, where the bolted connection is made in a threaded blind hole in the spider or the rim. The bolted connection without flats is not feasible for this type of threaded connection, since it would not be possible to tighten the bolted connection if a nut or bolt head without flats were provided.
A surface with knurling or a coefficient of friction increased in another way can be provided as the anti-rotational element. In particular, it can be provided that the spacer sleeve has a surface with an increased coefficient of friction at least in sections.
In particular it can be provided that the contact surface for the bolted connection is recessed with respect to the outer surface of the spider. A certain recess will always be necessary, at least in those cases in which the spider has a curved or angled outer surface, in order to ensure a level contact surface for the spacer sleeve and thereby the bolt or nut. The recess can be formed to different depths, where the distance by which the bolt extends above the surface of the spider can be determined through the height of the spacer sleeve.
It is particularly advantageous if the contact surface and thus the recess provided in the spider to seat the bolted connection essentially matches the dimensions of the spacer sleeve. This ensures that no surfaces are created at the base of the recess which are difficult to reach with cleaners.
The wheel can be formed in two or three parts, and the bolted connection can also represent a purely decorative item in the case of a one-piece wheel. A blind hole into which a thread has been cut matching the bolt thread can be provided in the rim for the bolted connection.